The present invention relates to apparatus and also to a method for controlling aircraft. The invention is particularly applicable for stabilizing remotely-controlled aircraft, such as model planes, target planes, and small remotely-piloted vehicles (RPV's), with respect to roll and pitch, and is therefore described below with respect to this application.
Many techniques have been proposed for providing remotely-controlled aircraft, such as model planes, with roll and pitch stabilization.
One known system for providing roll stabilization includes wing levellers; while this system produces reasonably good longterm stability, it is characterized by poor response to immediate command changes. Another known system for providing roll stabilization, and also pitch stabilization, includes a vertical gyro; however, this system is generally characterized by high power requirements, weight and price, and low reliability.
One known system for providing pitch stabilization includes a rate-gyro, but this system produces dynamic stabilization without position stabilization; that is, it generally does not maintain level flight for long time periods. A further known system for providing pitch stabilization includes mechanical or electro-mechanical height-hold altitude transducers, which sense the aircraft's rate-of-climb; such systems, however, are not precise because of hysteresis and low sensitivity, and are therefore usually suitable only to maintain level flight. A further known system includes electro-static stabilization; the disadvantages of such a system, however, include sensitivity to local climate changes and atmospheric disturbances, and the requirement for radioactive materials for plating the sensing electrodes.